Compact inflatable device for applying localized pressure to turbine generator armature bars

ABSTRACT

Radial pressure is applied to a turbine generator armature bar using a simple hand held device that can be readily manipulated by a single human operator. A retainer platform has two wedge shaped portions with handles, and by the operator sliding the wedge shaped portions with respect to each other the operative width of the platform may be adjusted, including to slide and lock the platform in a conventional dovetail slot in a stator. An inflatable bladder is positioned on or mounted to the top surface of the platform and is dimensioned so as to apply radial pressure (for example through a filler) to armature bars mounted in the stator. A conduit, preferably having a valve with quick-release actuator in it, extends from the inflatable bladder and connects to a source of gas under pressure.

BACKGROUND OF THE INVENTION

During the process of winding a generator stator (such as shown in U.S.Pat. No. 4,572,980, the disclosure of which is hereby incorporated byreference), there is a need at several points in the process to applyradial pressure to the armature winding elements, commonly referred toas armature bars, to firmly force the bars and other slot contentsagainst the bottom of the stator core slot. The conventional device forapplying the pressure is an expandable strut containing a hydraulic ramwith jacking boards at both ends for distributing the applied force. Thestrut is positioned radially across the inside diameter of the statorcore and the jacking boards are placed within two diametrically oppositeslots. The hydraulic ram is pumped to a known pressure resulting in apressure applied to the armature bar areas contacted by the jackingboards. The bar-jacking device is heavy, bulky, and cumbersome to use.Two operators are needed to set up and use the device. During use of theconventional device, access to the bore of the stator core is restricteddue to the size and span of the device. The conventional device alsoholds the potential for leakage of the hydraulic fluid and contaminationof the stator core and armature winding.

BRIEF SUMMARY OF THE INVENTION

According to the present invention a turbine generator armature barpressure applicator, a turbine generator stator assembly, and a methodof mounting armature bars in a turbine generator stator, are providedwhich are simple and easy to use. The applicator according to theinvention is compact, hand-held, and lightweight (and hence portable),so that it can be used by a single operator during conventional windingor re-wedging processes. The device also has no potential forcontaminating the stator core and armature winding, or any accessorystructures.

According to one aspect of the present invention there is provided aturbine generator armature bar pressure applicator, comprising: Aretainer platform having first and second portions mounted to slide withrespect to each other to adjust the operative width of the platform, andconfigured to slide in a dovetail slot in a stator for receipt ofarmature bars, the platform having a top surface. An inflatable bladderoperatively associated with [for example mounted to, resting on, or inany other way associated with so that the desired functionality isprovided] the top surface and dimensioned so as to apply radial pressureto armature bars mounted in a stator. And, a conduit extending from theinflatable bladder for supplying gas under pressure to the bladder toselectively inflate the bladder.

The applicator preferably further comprises a valve operativelyconnected to the conduit for selectively allowing pressurized gas topass through the conduit into the bladder. or for venting pressurizedgas from the bladder; preferably the valve may be a conventional valvethat has a quick-release function, so that the bladder may be ventedquickly. The inflatable bladder may comprise a wide variety of differentstructures, such as a flexible wall hose.

Typically the applicator further comprises at least one handle mountedto the platform opposite the top surface. Desirably the platform isdimensioned and constructed so as to be readily handled by a singleperson (e.g. a normal adult male). The platform typically comprisesfirst and second portions that are generally wedge-shaped, and the atleast one handle comprises first and second handles each substantiallycentrally located in first and second portions, respectively.

According to another aspect of the present invention a turbine generatorstator assembly is provided, comprising: A turbine generator statorhaving a plurality of generally radially extending slots each with anaccess opening, and a dovetail slot in the stator adjacent the openingsand extending generally perpendicular to the radial slots. A pluralityof armature bars are inserted in at least one of the radial slots. Aninflatable bladder operatively engaging the armature bar, the bladderoperatively connectable to a source of gas under pressure. A hand heldplatform mounting the bladder and slidable in the dovetail slot. And,the bladder provided with gas under pressure to expand and apply radialpressure to the armature bars to press the armature bars into the radialslot, and the bladder vented to release gas under pressure from thebladder.

Typically there is at least one filler between the bladder and thearmature bars. The bladder is typically operatively connected to asource of gas under pressure by a conduit, and the assembly furthercomprises a valve operatively connected to the conduit for selectivelyallowing pressurized gas to pass through the conduit into the bladder,or for venting pressurized gas from the bladder. The valve preferablycomprises a quick-release valve. Typically there is at least one handlemounted to the platform opposite the top surface, and the inflatablebladder may comprise a flexible wall hose.

According to another aspect of the present invention there is provided amethod of mounting armature bars in a turbine generator stator having aplurality of generally radially extending slots each with an accessopening, and a dovetail slot in the stator adjacent the openings andextending generally along the radial slots, and using an inflatablebladder on a hand held platform, the method comprising, substantiallysequentially: (a) Inserting an armature bar in one of the radial slotsthrough the access opening. (b) Moving the inflatable bladder intooperative engagement with the armature bars, including by moving theplatform in the dovetail slot. (c) Supplying gas under pressure to thebladder to expand the bladder and apply radial pressure to the armaturebars to press the armature bars into the radial slot through the accessopening. (d) Venting gas under pressure from the bladder so that thebladder is no longer in operative engagement with the armature bar.

Preferably the platform comprises first and second wedge-shaped portionsslidable with respect to each other to adjust the effective widththereof and each portion having at least one handle; and in the methodpreferably (b) is practiced by manually moving the portions with respectto each other by engaging the handles so that the platform is of a widththat will slide in the dovetail slot until the bladder is aligned withthe armature bar; and then manually moving the handles with respect toeach other to cause the platform to have a width that causes theplatform to be substantially wedged in a stationary position in thedovetail slot. The method also preferably further comprises, between (a)and (c), inserting at least one filler between the bladder and thearmature bar. Desirably the inflatable bladder has a quick-release valveoperatively associated therewith, and (d) is practiced by manuallyactuating the quick-release valve. In the method, (c) may be practicedto supply gas under a pressure of about 80-120 (e.g. about 100) psi tothe inflatable bladder.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a detail side view, partly in cross-section and partly inelevation, of one form of an applicator according to the presentinvention shown mounted in association with a turbine generator statorso as to apply radial pressure to an armature bar in the stator;

FIG. 2 is a top plan view of the platform (only) of the applicator ofFIG. 1; and

FIG. 3 is a side schematic view, with portions of the platform cut awayfor clarity of illustration, of the applicator of FIGS. 1 and 2 with theinflatable bladder inflated.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an exemplary turbine generator stator core 10 (suchas shown in U.S. pat. 4,572,980) having a plurality of radiallyextending slots 11 each with an access opening 12 (see FIG. 4) anddovetail slot 13 adjacent the openings 12 and extending generally alongthe slots 11. Armature bars 14 are typically mounted in each of thebores 11, typically, although not necessarily, with one or more fillerelements 15 at the opening 12. According to the present invention asimple turbine generator armature bar pressure applicator 17 is providedwhich can be utilized to simply, easily, and effectively, apply thedesired radial pressure to the armature bars 14.

The applicator 17, in the preferred embodiment illustrated in thedrawings, a platform 16 which in turn comprises first and second bodyportions 18, 19 which are preferably substantially wedge-shaped (seeFIG. 2) and mounted together, using any suitable groves, channels, orsurface manifestations, such as shown schematically at 20 in FIGS. 1through 3, to adjust the operative width 21 thereof (see FIG. 1). Theplatform 16, and specifically the ends of the components 18, 19 areconfigured to slide in the dovetail slot 13, and has a top surface 22.

While other configurations may be provided, the platform 16 may have atleast one handle 23, 24 extending downwardly from a substantiallycentral portion of each of the sections 18, 19, respectively so that asingle human operator may grasp the handles 23, 24 and move them withrespect to each other in the direction of elongation of theplatform—indicated by the arrows 25 in FIGS. 2 and 3—to effect therelative sliding action, and width adjustment.

An inflatable bladder, such as the flexible wall hose 27 illustrated inFIGS. 1 and 3, is operatively associated with the top surface 22 ofplatform 16. The operative association may be by a wide variety ofdifferent methods. For example the hose 27 could be fixed by adhesive,mechanical fasteners (with appropriate sealing), or like devices to oneof the sections 18, 19; or it may be loosely laid on top of the surface22; or it may be associated with the surface 22 in any other suitablemanner, as long as the bladder 27 may be operated so as to apply aradial pressure to the armature bars 14. FIG. 1 shows the hose 27 in acollapsed condition, whereas FIG. 3 shows the hose 27 in an expandedcondition. That is, FIG. 1 shows the hose 27 after venting, and FIG. 3shows the hose 27 when pressurized with compressed gas (e.g. air) from aconventional source 29 (see FIG. 3) of compressed air.

Typically a conduit—such as a flexible conduit—shown schematically at 30in FIG. 3—extends between the bladder 27 and the source of compressedgas 29. The conduit 30 may extend through one of the sections (e.g. thesection 18 as seen in FIG. 3) of the platform 16 out through the bottomthereof, so that the conduit 30 does not interfere with the movement ofthe platform 16 in the dovetail slot 13, or the radial movement of thebladder 27.

In order to selectively control supply of compressed gas under pressure(e.g. between about 80-120 psi, preferably about 100 psi) from thesource 29 to the bladder 27, a conventional valve 32 (see FIG. 3) may beprovided. The valve 32 may be mounted to the bottom of one of thesections (e.g. section 18 in FIG. 3) of the platform 16, and preferablyis a valve that has three positions, a first position in which gas underpressure flows from the source 29 to the bladder 27 to inflate it, asecond position in which gas is vented from the bladder 27 to atmosphere(or a recovery tank), and a third position in which the valve 32 isclosed and gas does not move into or out of the bladder 27. While a widevariety of conventional valves 32 for that purpose may be utilized,preferably the valve 32 includes a manual actuator 33 of the“quick-release” type, so that when the actuator 33 is manually actuatedthe pressurized gas quickly vents from the bladder 27, and when theactuator 33 is released, the bladder 27 is in a position awaiting thenext connection to the source of compressed gas 29.

In the practice of an exemplary method according to the presentinvention, armature bars 14 are inserted into a slot 11 in the statorcore 10 through the access opening 12, and if desired a filler 15 isalso inserted. The inflatable bladder 27 is moved into operativeengagement with the armature bars 14 (e.g. into a position abutting oneor more fillers 15, or simply underlying the armature bars 14),including by moving the platform 16 in the dovetail slot 13 when thehandles 23, 24 have been moved to a position where the width 21 isslightly less than the normal width of the dovetail slot 13. When thebladder 27 is in proper alignment with the armature bars 14 then thehandles 23, 24 are grasped so as to move the sections 18, 19 so that thewidth 21 is substantially the same as the width of the slot 13, and sothat the platform 16 is substantially wedged in a stationary position inthe dovetail slot 13. Then gas is supplied under pressure to the bladder27, such as by manually actuating the valve 32 to allow compressed airto flow from the source 29 to the bladder 27 through the conduit 30, andthe gas under pressure expands the bladder 27 so that it applies aradial pressure to the armature bar 14 to press the armature bars 14into the bore 15 through the access opening 12. After the appropriatepressure (e.g. about 100 psi) has been applied, then the gas is ventedfrom the bladder 27 (for example by manually actuating the quick-releaseactuator 33 of the valve 32) so that the bladder 27 is no longer inoperative engagement with the armature bars 14. Then the aboveprocedures are repeated for at least one additional pair of armaturebars 14.

It will thus be seen that according to the present invention a simpleyet effective turbine generator armature bar pressure applicator hasbeen provided, eminently suited for use in a turbine generator statorassembly, and in a method of mounting armature bars in a turbinegenerator stator. While the invention has been herein shown anddescribed in what is presently conceived to be the most practical andpreferred embodiment thereof it will be apparent to those of ordinaryskill in the art that many modifications may be made thereof within thescope of the invention, which scope is to be accorded the broadestinterpretation of the appended claims so as to encompass all equivalentstructures and methods.

What is claimed is:
 1. A portable turbine generator armature barpressure applicator for use in a stator assembly procedure, comprising:a retainer platform having first and second portions mounted to slidewith respect to each other to adjust an operative width of saidplatform, said first and second portions having ends configured to slidein a dovetail slot in a stator for receipt of armature bars, saidplatform having a top surface; an inflatable bladder operativelyassociated with said top surface and dimensioned so as to apply radialpressure to an armature bar mounted in a stator; and a conduit extendingfrom said inflatable bladder for supplying gas under pressure to saidbladder to selectively inflate said bladder.
 2. An applicator as recitedin claim 1 further comprising a valve operatively connected to saidconduit for selectively allowing pressurized gas to pass through saidconduit into said bladder, or for venting pressurized gas from saidbladder.
 3. An applicator as recited in claim 2 wherein said valve has aquick-release actuator.
 4. An applicator as recited in claim 1 furthercomprising at least one handle mounted to said platform opposite saidtop surface.
 5. An applicator as recited in claim 4 wherein saidplatform is dimensioned and constructed so as to be readily handled by asingle person.
 6. An applicator as recited in claim 4 wherein saidplatform first and second portions are generally wedge shaped.
 7. Anapplicator as recited in claim 6 wherein said at least one handlecomprises first and second handles each substantially centrally locatedin first and second portions, respectively.
 8. An applicator as recitedin claim 1 wherein said inflatable bladder comprises a flexible wallhose.
 9. An applicator as recited in claim 6 further comprising a valveoperatively connected to said conduit for selectively allowingpressurized gas to pass through said conduit into said bladder, or forventing pressurized gas from said bladder.
 10. An applicator as recitedin claim 9 wherein said valve has a quick-release actuator.
 11. Anapplicator as recited in claim 10 wherein said inflatable bladdercomprises a flexible wall hose.
 12. A portable turbine generatorarmature bar pressure applicator for use in a stator assembly procedure,comprising: a retainer platform having first and second wedge-shapedportions mounted to slide with respect to each other to adjust anoperative width of said platform, said first and second portions havingends configured to slide in a dovetail slot in a stator for receipt ofarmature bars, said retainer platform having a top surface; aninflatable bladder operatively associated with said top surface anddimensioned so as to apply radial pressure to an armature bar mounted ina stator; a conduit extending from said inflatable bladder for supplyinggas under pressure to said bladder to selectively inflate said bladder;a valve operatively connected to said conduit for selectively allowingpressurized gas to pass through said conduit into said bladder, or forventing pressurized gas from said bladder; and first and second handleseach substantially centrally located in said first and second portions,respectively, and extending away from said ends.